struct ListNode* FindKthToTail(struct ListNode* pListHead, int k)
{
	if(pListHead==NULL)
	{
		return NULL;
	}
	
	struct ListNode*slow,*fast;
	slow=fast=pListHead;
	while(k--)
	{
		if(fast==NULL)
		{
			return NULL;
		}
		fast=fast->next;
	}
	while(fast)
	{
		slow=slow->next;
		fast=fast->next;
	}
	return slow;
}
